Adjustable, locking armrest for chair

ABSTRACT

An armrest that is infinitely adjustable is provided by the combination of a pin and slot arrangement for adjusting the arm in one direction and a second pin and slot arrangement for angularly adjusting the arm in a different direction, the second pin being in the form of a locking cam which locks the arm to a portion of the chair.

FIELD OF INVENTION

This invention relates to an armrest support for the arms of a personseated in a chair, and more particularly to an armrest which isinfinitely adjustable within the parameters of its movement to supportthe arm of a seated person regardless of the person's size and bodygeometry.

BACKGROUND OF THE INVENTION

Armrests on chairs are usually fixed in one position. Some chairs haveadjustable arms which are limited in their range of motion. Conventionalmovable armrests lock at specific default positions provided by themanufacturer. Adjustable armrests typically have a shaft with a sleevefor adjustable vertical movement, and/or have an adjustable angle usinga pivot attached to the armrest.

Inasmuch as the geometry and comfortable positions of every human beingis slightly different from that of other human beings, the ideal armrestwould be one which is totally and infinitely adjustable in all threedimensions to accommodate the sitter no matter what his or her geometry.Also, the actual portion of the armrest that comes into contact with thesitter's arm should minimize pressure on the sitter's arm so as not toimpede circulation or cause nerve pressure. In order to accomplish theseends, the armrest must be lockable in whatever position the sitterrequires to be comfortable.

SUMMARY OF THE INVENTION

Problems with the prior art are solved by the present invention, whichprovides an adjustable armrest device that supports the sitter's arm.The portion of the armrest that comes into contact with the person's armis preferably of thick, soft, foamed plastic which is large enough todistribute the weight of a person's arm over a relatively large area,thereby causing little or no point pressure. The device to which thefoamed plastic is attached is preferably made of steel or other metal,or high density plastic. The armrest structure is adjustable angularlyin the anterior-posterior plane and also adjustable vertically. The armstructure is fixed to the chair and has a locking mechanism to hold thecontacting portion of the armrest wherever the sitter desires. The armstructure can utilize a triangular arrangement rigid within the plane ofthe armrest when locked.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an adjustable, lockable arm rest.

FIG. 2 is a front view of an assembled adjustable, lockable arm rest,and

FIG. 3 is a bottom view of an arm on which the armrest is supported.

FIG. 4 is a front view of a friction disk, the rear view beingidentical, and

FIG. 5 is a cross section thereof.

FIG. 6 is a side view of a locking shaft and cam assembly.

FIG. 7 is a plan view of a bracket with a 90 degree slot, FIG. 8 is aplan view of a bracket with a 180 degree slot, and FIG. 9 is a side viewof the bracket of FIG. 7 and FIG. 8.

FIG. 10 Is a side view of an alternate structure of the arm using astrut.

FIG. 11 is a front view of an embodiment of a bracket and locking shaftand cam assembly.

FIGS. 12A and 12B are side and plan views of another embodiment of thefriction disk.

FIGS. 13A and 13B are front and side views of an embodiment of thebracket.

BRIEF DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring initially to FIGS. 1 and 2, the present invention is directedto an armrest and armrest support of a chair that, in certainembodiments, utilizes the principle of the triangle for its strength andto achieve its function; that is, a structure having three segmentsattached at their ends to form a triangle. As can be seen, in the planeof the triangle the arm can be moved to infinite positions within itsrange of movement.

In FIG. 1, the arm 2 of the chair includes an armrest pad 1 on which thesitter rests his arm. (Although described with reference to an armrest,the present structure could be used for an adjustable foot rest aswell.) The pad is preferably sized so that regardless of the angle atwhich the arm is disposed, the user will have an adequate surface onwhich the rest his arm. The arm includes an arm slot 7 runningsubstantially down its length and having a bulbous portion at one end ofthe slot that is wider than the slot width. Swivel pin 5 extends from abracket 3 having a generally planar face and which is attached to themain chair structure (not shown), such as to the seat 18. The swivel pinhas a bulbous head and a shaft portion, the shaft portion beingsufficiently small to fit and be moveable within the arm slot, and thebulbous head being sufficiently small to fit within the bulbous portionof the arm slot but sufficiently large to retain the arm on the swivelpin. The swivel pin is equidistant with the points forming the bracketslot 9 formed in the bracket. That is, the bracket slot is preferably anarcuate slot having as its origin the swivel pin. The bracket slot couldalso be linear, or have a different curvature, but the preferredembodiment is an arc centered on the swivel point. The arm 2 can bepivotally adjusted on the swivel pin through the extent of the bracketslot 9 and longitudinally adjusted through the longitudinal length thearm slot 7.

In FIG. 2, it is seen that the bracket has an angled cantileveredportion 3 a which is attached to the main chair structure, angled withrespect to the bracket portion 3 to which the arm is attached. Thoughnot preferred, the end of the swivel pin can be threaded and a screwedclosure applied, or the pin can otherwise be capped with a deviceallowing movement along the slot but being wider than the slot.Positioned between the arm and the bracket and disposed around theswivel pin is a washer 12.

In FIGS. 2 and 3, the base 14 of the arm pad 1 is of a hard materialsuch as plywood, plastic, or metal, and is affixed to the horizontalportion of the arm 2 a in which is a located an pad slot 2 b. The padmay be moved laterally towards and away from the arm by moving the padalong the pad slot, and loosening and tightening using the pad fixationdevice 17, preferably a screw-like device extending through the slot andengaging the base of the pad.

Referring to FIGS. 2 and 4, another portion of the bracket is attachedto the arm by a locking mechanism, which is preferably a locking cam,but can be a threaded screw-like device. In the preferred camembodiment, a locking rod 13 extends through both the arm slot and thebracket slot. The locking rod can be threaded at one end and secured bya cap nut 4, with a washer 16 between the cap nut and the bracket.Disposed between the bracket and the arm is a friction disk, describedbelow. On the opposite side of the arm is a cam having lever 11 having afree end and an opposite cam end engaging a washer 15 that abuts thearm. The cam end of the lever is pivotally attached to the locking rod;the lever is shown in the locked position wherein the cam applies forceto the arm through the washer; when unlocked (lever rotated to the leftin FIG. 6) the pressure is released, allowing the arm to be moved withinthe two slots. When the cam is unlocked the arm can be moved freely sothat the sitter can adjust the angle and position of the arm to whereverdesired, to get in a comfortable position to rest or read or eat or anyother action one takes when sitting.

The friction disk is shown in FIGS. 4 and 5. Because the cam force maynot be sufficient by itself to lock the arm if sufficient weight isapplied to the arm (such as by someone sitting on the pad), thisinvention utilizes a friction disk. As shown in these figures, thefriction disk 6 is like a washer having a bore through the center, and aflange 8 that extends orthogonally from both sides of the washer (asshown in FIG. 5). The friction disk, being disposed between the arm andthe bracket, contacts both the arm and the bracket at the flange,providing significantly less contact area than would a simple washer,and hence a higher frictional force. Thus, the cam force is transmittedto a smaller area, providing an effective greater force per area to keepthe arm locked. While the flange is shown as continuous for ease ofmanufacture, the flange can be discontinuous, or may only be provided asa plurality or multiplicity of raised portions on one or both sides ofthe friction disk, the idea being to minimize the contact area and soprovide a greater frictional force for locking the arm. Likewise,although shown in a circular geometry, the friction washer could berectilinear or another geometry. Although not preferred, the frictiondisk can be eliminated by providing raised portions adjacent each of thearm slot and bracket slot along substantially the length of each slot,whereby the arm and the bracket thus contact each other only where theraised portions meet, again providing a reduced contact surface and ahigher frictional force. Alternatively, instead of a lever cam ascrew-type knob can be provided, with the locking arm being threaded, totighten the structure and provide the desired compressive force.

FIG. 7 depicts the bracket as shown in FIGS. 1 and 2 with a slotextending 90 degrees. FIG. 8 depicts a bracket having a slot thatextends 180 degrees. FIG. 9 is a side view of either FIG. 7 or FIG. 8for the preferred embodiment wherein the bracket is cantilevered fromthe underside of the seat. Of course, a slot of any length can be useddepending on the desired range of movement for adjusting the arm.

In operation, the user of the chair unlocks the lever, adjusts theheight and orientation of the arm along the arm slot and the bracketslot, and locks the cam with the lever, fixing the arm position. Anadvantage of the two slots and in combination with the locking cam isthat the user need not rely on fixed serial adjustment points asprovided in existing armrests, which provide digital setpoints, but canadjust the arm infinitely (analog) in any desired position within theavailable range of movement allowed by the slots.

In another embodiment, shown in FIG. 10, the seat 18 is seen in sideview (alternatively, 18 can be a bracket attached to the chair or seat).Affixed to the seat is a strut pivot 17 attached to fixation strut 22having a strut slot 20 running substantially its length. Also affixed tothe seat 18 is the a swivel pin 19 that extends through arm slot 21 inarm 23 and has a bulbous end like swivel pin 5. Where the arm 23 and thestrut 22 cross is a locking rod 13 similar to the rod of lockingmechanism in FIGS. 1, 2, and 4, and the associated structure of thelever and friction disk disposed between the arm and the strut. This rodgoes through the slots 20 and 21, thereby pivotally connecting them. Asdescribed above, when the desired position is achieved, the lever cam 11is locked. The pins 17 and 19 form the fixed side of a triangle, andwhen the lever is locked the other two legs of the triangle becomefixed, thereby locking the arm and strut orientation to the chair andproviding a locked and secured structure.

In another embodiment, as shown in FIG. 11, the locking force of thefriction disk can be directed to opposing sides of the arm. An annularfriction disk 101 having a single face with a flange 102 is disposed onshaft 107. One end of the shaft provides connection to a lever 108 atpivot 109, the lever including a cam portion 112. that acts on the diskface opposite from the face having the flange. The cam portion of thelever is preferably U-shaped. Bracket 103 having a bottom portion 103 ahas an orifice though which the other end of the rod projects and issecured by cap 110, with a washer 111 between the cap and the inside(side facing the person seated) of the flange. Attached to the outsideof the bracket is a friction portion 113 having a flange 115. Themechanism is disposed about the arm, as described above, with the camlever compressing the flanges 102 and 115 against opposite sides of thearm.

In an especially preferred embodiment, the arrangement shown in FIG. 11includes a square bore in the friction disk, the friction portion, orboth. As seen in FIGS. 12A and 12B, side and plan views, respectively,of a friction disk suitable for use in the apparatus of FIG. 11, thebore 121 can be non-round; a square embodiment is shown. Of course, theportion of the locking shaft passing through should also be square.Although a square embodiment has been shown, the bore could betriangular, rectangular, or any regularly shaped polygon, or anirregularly shaped polygon, or oval, or hemispherical. In essence, by“non-round” is meant a geometry between the bore and the rod that doesnot allow rotation between the disk and the rod. The non-rotatingarrangement can also be used on the bracket, as shown in FIGS. 13A and13B, side and front views, respectively, of the backet attached to thechair 118.

FIG. 14 is another embodiment where the arm does not have a slot (thecamming clamp mechanism is not shown). In this case the arm 1401 is asolid piece having one or more extensions 1403 on which the arm rest1405 is supported.

While the foregoing has been described with respect to a chair, it isevident that this invention can find use in fixed seating devices, suchas seats on planes, buses, cars, and other vehicles, or in movietheaters, or on wheelchairs. While armrests are typically provided onseating devices, the armrests could instead be attached to a structuresuch as a workbench, desk, table, or podium. The armrest is mostpreferably used with the chair as described in U.S. Pat. No. 6,244,659,the disclosure of which is incorporated herein by reference.

The foregoing description is meant to be illustrative and not limiting.Various changes, modifications, and additions may become apparent to theskilled artisan upon a perusal of this specification, and such are meantto be within the scope and spirit of the invention as defined by theclaims.

1. An armrest for a chair, comprising: a. an arm having a longitudinalarm slot therein; b. a bracket having a generally planar face connectedto the chair, the bracket having a swivel pin on which the arm isdisposed at the arm slot; c. a friction disk having a bore and disposedbetween the arm and the bracket; and d. locking means for compressingthe arm, bracket, and friction disk together to lock the arm in place.2. The armrest of claim 1, further comprising an arm pad.
 3. The armrestof claim 1, wherein the locking mechanism is a levered cam.
 4. Thearmrest of claim 1, wherein the locking washer has a continuous flangeon at least one face.
 5. The armrest of claim 1, wherein the lockingwasher has a discontinuous flange on at least one face.
 6. The armrestof claim 2, further comprising means for laterally adjusting theposition of the pad.
 7. The armrest of claim 1, wherein said lockingmeans comprises a locking rod passing through the arm slot, the bore ofthe friction disk, and the bracket slot, one end of the locking rodbeing fixed, the other end of the locking rod having a locking mechanismfor compressing the arm, friction disk, and bracket together.
 8. The armrest of claim 7, wherein the locking mechanism is a cam.
 9. The armrestof claim 8, wherein the cam is a portion of a lever pivotally attachedto the locking rod.
 10. The armrest of claim 1, wherein the lockingmeans comprises a locking rod passing through the arm slot, the bore ofthe friction disk, and the bracket slot, one end of the locking rodbeing fixed, the other end of the locking rod having being threaded andhaving a knob with a corresponding thread for compressing the arm,friction disk, and bracket together.
 11. An armrest for a chair,comprising: a. an arm having a longitudinal arm slot therein; b. a struthaving a strut slot substantially along its length and being pivotallyattached to the chair; c. a friction disk having a bore and disposedbetween the arm and the strut; and d. locking means for compressing thearm, the strut, and the friction disk together to lock the arm in place.12. The armrest of claim 11, wherein said locking means comprises alocking rod passing through the arm slot, the bore of the friction disk,and the bracket slot, one end of the locking rod being fixed, the otherend of the locking rod having a locking mechanism for compressing thearm, friction disk, and bracket together.
 13. The arm rest of claim 12,wherein the locking mechanism is a cam.
 14. The armrest of claim 13,wherein the cam is a portion of a lever pivotally attached to thelocking rod.
 15. The armrest of claim 11, wherein the locking meanscomprises a locking rod passing through the arm slot, the bore of thefriction disk, and the bracket slot, one end of the locking rod beingfixed, the other end of the locking rod having being threaded and havinga knob with a corresponding thread for compressing the arm, frictiondisk, and bracket together.
 16. An armrest for a chair, comprising: a.an arm having a bore therein; b. a bracket having a generally planarface connected to the chair, the bracket having an upstanding portion;c. friction disk means between the arm and the bracket selected from thegroup consisting of a friction disk disposed therebetween, a frictiondisk integral with the bracket, or a friction disk integral with thearm, said friction disk means having a bore therein; and d. lockingmeans for compressing the arm, bracket, and friction disk means togetherto lock the arm in place.